Finding the Fourth Proportional to 1,081.51, 1,492.42 and 639.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.51 : 1,492.42 = 639.25 : x
2. Step 2: Convert to fraction form
   1,081.51/1,492.42 = 639.25/x
3. Step 3: Cross multiply
   1,081.51x = 1,492.42 × 639.25
4. Step 4: Simplify right side
   1,081.51x = 954,029.49
5. Step 5: Solve for x
   x = 954,029.49/1,081.51
6. Step 6: Final answer
   x = 882.13